One of the things that makes a big difference with sleep on international flights is the timing of the second meal service.

Most of my international flying is on United, and I notice they never begin the pre-arrival meal service until 1:20 before arrival, in both C and Y. On other carriers it is normally 2:00 before arrival. This gives me an extra :40 of sleep, which is much appreciated.

I agree the timing of duty free, after the first meal service, is extremely annoying. They should do the duty free service between the first drink service and first meal service, or just get rid of it altogether.

We can't do much about aisle traffic, whether it be F/As or passengers. People have to get up and move. I find myself routinely bumping into people who have their feet and elbows protruding into the aisle. It can often be a real challenge to walk through the aisle during the night.